输出文件的新行不是从下一行开始的

Question

我的空间有问题。如何正确打印输出文件？当我运行我的代码时，就像。。。。。

这就是我的主方法的样子，并生成输出文件。。。。。

main()....{
File stats = new File(statFile);
    stats.createNewFile();
// my code here.... the stat values change here.

    FileWriter statFileWriter = new FileWriter(stats, true);
    BufferedWriter statsOutput = new BufferedWriter(statFileWriter);
    statsOutput.write(Stats.printStat());
    statsOutput.flush();
}

这是Stat类，我可以在程序中更改值，并打印出带有值的字符串。

public class Stats {
public static String dataFile = "";
public static int cacheHits = 0;
public static int diskReads = 0;    
public static int diskWrites = 0;
public static long executionTime = 0;
public static String printStat() {
    String print = "";
    print += "Sort on " + dataFile;
    print += "nCache Hits: " + cacheHits;
    print += "nDisk Reads: " + diskReads;
    print += "nDisk Writes: " + diskWrites;
    print += "nTime is " + executionTime;
    return print;
}
}

这应该使输出像：

Sort on sorted_b.dat
Cache Hits: 30922
Disk Reads: 1
Disk Writes: 1
Time is 16
Sort on sorted_a.dat
Cache Hits: 62899
Disk Reads: 2
Disk Writes: 2
Time is 0

但是当我在测试用例中运行main两次时，实际输出是：

Sort on sorted_b.dat
Cache Hits: 30922
Disk Reads: 1
Disk Writes: 1
Time is 16Sort on sorted_a.dat    ------> the new stat is not start from the nextline.
Cache Hits: 62899
Disk Reads: 2
Disk Writes: 2
Time is 0

如果我在print+="\nTime is"+executionTime；这条线，就像print+="\nTime is"+executionTime+\n；

它会在最后多做一行，就像一样

Sort on sorted_b.dat
Cache Hits: 30922
Disk Reads: 1
Disk Writes: 1
Time is 16
Sort on sorted_a.dat
Cache Hits: 62899
Disk Reads: 2
Disk Writes: 2
Time is 0
          ------------blank, but extra line.

如何在没有额外行的情况下打印输出，并正确打印？

Answer 1

将主方法更改为：

File stats = new File(statFile);
Boolean fromStart = stats.createNewFile();
// my code here.... the stat values change here.  
FileWriter statFileWriter = new FileWriter(stats, true);
BufferedWriter statsOutput = new BufferedWriter(statFileWriter);
if(fromStart == false) statsOutput.write("n");
statsOutput.write(Stats.printStat());
statsOutput.flush();

从stats.createNewFile()返回的Boolean fromStart将是：

• true如果是第一次创建文件-->则无需添加额外的换行符
• false（如果文件已经存在）-->在写入新内容之前需要添加新行

Answer 2

您需要在末尾附加额外的"\n"

public class Stats 
{
public static String dataFile = "";
public static int cacheHits = 0;
public static int diskReads = 0;    
public static int diskWrites = 0;
public static long executionTime = 0;
    public static String printStat() 
    {
        String print = "";
        print += "Sort on " + dataFile;
        print += "nCache Hits: " + cacheHits;
        print += "nDisk Reads: " + diskReads;
        print += "nDisk Writes: " + diskWrites;
        print += "nTime is " + executionTime+"n";
        return print;
    }
}

Answer 3

在主方法中，只需使用BufferedWriter的newLine()方法，如下所示：

FileWriter statFileWriter = new FileWriter(stats, true);
BufferedWriter statsOutput = new BufferedWriter(statFileWriter);
statsOutput.write(Stats.printStat());
statsOutput.newLine();

如果你愿意，你也可以在写统计数据之前添加一行新行。